Bulk cartridge for packaging and dispensing a dental material

ABSTRACT

A dental syringe for the dispensing of a relative viscous dental material that includes a readily replaceable barrel portion that defines a reservoir for containing a bulk supply of a dental material having a spout or nozzle discharge end to which a dispensibly nozzle tip is detachably connected and which barrel portion is sealed by a displaceable plug. A plunger is provided for effecting the displacement of the plug for effecting the extruding of the material from the barrel portion as needed, and which plunger has formed on the end thereof a unidirectional vent arrangement which is operative for imparting a negative pressure on the end plug to permit a slight rearward displacement thereof to relieve the back pressure exerted on the plug by the material upon the termination of an extruding operation and thereby prevent drooling of any unwanted material subsequent to an extruding operation.

RELATED APPLICATION

This application is a division of my co-pending application, Ser. No.314,768 filed Oct. 28, 1981, entitled All Purpose Dental Syringe, nowU.S. Pat. No. 4,472,141 issue 9-18-84.

PROBLEMS AND PRIOR ART material,

This invention relates to improvements in dental syringes, and moreparticularly to improvements to the dental syringes disclosed in myprior U.S. Pat. Nos. 3,436,828; 3,581,399; 3,900,954; 4,198,756;D-224,655 and pending patent application Ser. No. 251,278 filed Apr. 6,1981.

Heretofore various known techniques and implements have been used bydentists to deliver or handle a particular dental material as may berequired for the various known dental procedures. However, prior to thisinvention each type of material used in the various dental proceduresrequires its own specialized delivery or handling tool or instrument.For example, a particular type of anesthesis syringe was required toadminister an anesthesia. Another implement or tool was required todeposit a filling material in a cavity. Root canal work requiredcompletely different sets of implements. In still other procedures, suchas the taking of impressions, other types of implements or tools wererequired. As a result a dentist needs a host of varying types and kindsof implements, syringes, tools, spatulas and the like to perform and/orotherwise administer or handle the various different kinds of dentalmaterials required for the many and various dental procedures dailyperformed by such dentists. With the ever increasing advances indentistry, new dental materials are being constantly developed, whichrequire a new and more efficient means for the handling, administeringor working with such material, e.g. the composite resins and thechemicals setting epoxies and/or light settable materials. The presentinvention has been developed so as to facilitate the handling anddelivery of the various dental materials in a simple and expedientmanner.

OBJECTS

It is therefore an object of this invention to provide for an improvedall purpose delivery system or syringe which can be readily adapted todeliver or dispense a variety of different dental materials, e.g.anesthesia, root canal material, various filling materials and/orcomposite resins, light setting material, impression material, and thelike, thereby substantially reducing the number of tools or implementsotherwise required to effect the delivery of such materials.

Another object is to provide an all purpose dental syringe which isrelatively simple in construction, can be readily manufactured, andwhich is positive in operation.

Another object is to provide an all purpose dental syringe in which thecomponents required to effect the delivery of a particular material areinterchangeable with respect to a common power handle.

Another object is to provide for a multi-purpose dental syringe in whichthe component parts are color coded for ease of assembly and use.

Another object is to provide an all purpose dental syringe in which theamount of the various materials dispensed thereby can be varied oradjusted according to need or desire.

Another object is to provide a carrier for containing a supply offilling material for storing or shipping such material and which carrierfunctions as component of an all purpose syringe.

Another object is to provide a syringe in which the dispensing of amaterial due to any residual pressure imparted on the material isprohibited.

Another object is to provide an improved all purpose syringe fordispensing light setting filling material and a cartridge for suchmaterial.

SUMMARY OF THE INVENTION

The foregoing objects and other features of this invention are attainedby an all purpose dental syringe for delivering various kinds of dentalmaterials as may be required for the various dental procedures. The allpurpose syringe comprises a power handle to which a plurality of barrelassemblies are interchangeably connected and each barrel assembly beingadapted to dispense a different type of of dental material, e.g. ananesthesia, composite resin, root canal material, impression material,hydrocolloid, chemical setting epoxies, light setting material and thelike. The power handle includes a pair of complementary handle sectionshaving a spring bias trigger mounted therebetween. A plunger isreciprocally mounted in the power handle and a drive pawl is operativelyassociated with the trigger to effectively advance the plunger as thetrigger is activated. A holding pawl is cooperatively associated withthe plunger to prohibit any backlash of the plunger as the drive pawl isretracted upon the release of the trigger. An adjustment is associatedwith the trigger to vary the throw thereof and thereby regulate thelinear advance of the plunger during a dispensing operation to controlor vary the amount of material dispensed.

The interchangeable barrels and the respective component parts areconstructed to accommodate a particular dental material. Complementingthe respective barrels is a plunger tip arranged to detachably connectto the plunger thereby adapting the plunger to extrude the materialdispensed by a particular barrel. By attaching the barrel containing theappropriate material to the common power handle, a dentist can effectthe delivery of any of several distinct dental materials withessentially the same instrument or syringe. In one embodiment the barrelis particularly constructed for dispensing and storing a supply of lightsetting material in a manner which prohibits the setting up of thematerial until it has been delivered. Another embodiment prohibitsdribbling or dispensing of the material from the nozzle due to residualpressure imparted on the material after an extruding operation.

FEATURES

A feature of the invention resides in the provision of an all purposedental syringe which comprises a power handle to which a plurality ofinterchangeable barrels can be readily connected to effect thedispensing of a variety of different types of dental materials which maybe required for various dental procedures.

Another feature resides in the provision of an improved carrier orcartridge construction particularly adapted for storing and dispensing alight settable material and/or other type of dental and/or medicalmaterials.

Another feature resides in a general purpose syringe which is capable ofdispensing both liquid and solid materials.

Another feature resides in a general purpose syringe which can bereadily adapted to dispense a variable proportion of dental materials asmay be desired.

Another feature resides in the provision of providing a dental syringewith interchangeable barrels and complementary plunger tips which areinterchangeable on a common power handle having a sufficient mechanicaladvantage to effect the dispensing of a relatively viscous materialthrough a relatively small gauge needle with a minimum of effort.

Another features resides in the provision of a multiple purpose syringehaving a power handle in the form of a piston grip to facilitate the useand operation thereof.

Another feature resides in the provision of a plunger which isconstructed in a manner so as to co-act with the holding pawl in amanner so as to prohibit unintentional removal of the plunger from thehandle portion of the syringe.

Other features and advantages will become more readily apparent whenconsidered in view of the drawings and detailed description in which

FIG. 1 is a side sectional view of the all purpose syringe embodying theinvention taken on line 1--1 on FIG. 2.

FIG. 2 is an end sectional view taken generally along line 2--2 on FIG.1.

FIG. 3 is a partial exploded side view of a handle section andassociated trigger.

FIG. 4 is a partial plan view of the other handle section.

FIG. 5 is an enlarged side sectional view of the syringe barrel assemblyfor dispensing a dental impression material.

FIG. 6 is a side sectional view of a syringe barrel assembly fordispensing a dental anesthesia or hydrocolloid.

FIG. 7 is a side sectional view of a syringe barrel assembly fordispensing a root canal material.

FIG. 7A is a sectional view taken on line 7A--7A on FIG. 7 and on FIG.8.

FIG. 8 is a side sectional view of a syringe barrel assembly fordispensing a composite resin filling material.

FIG. 9 is a side sectional view of a syringe barrel assembly fordispensing a light settable dental material or orthopedic cement.

FIG. 10 is a side sectional view of a modified syringe barrel assembly.

FIG. 11 is a detail sectional view of a sealing cap for use with thesyringe barrel assembly of FIGS. 9 and 10.

FIG. 12 is a side sectional view of another barrel assembly.

FIG. 13 is a side sectional view of a slightly modified embodiment of abarrel assembly and including a means to prohibit extruding material dueto residual pressures.

FIG. 13A is a partial sectional view of the assembly of FIG. 13,illustrating the parts in this operative position for relieving thepressure on the material.

FIG. 13B is a front end view of the valve body of FIGS. 13 and 13A.

FIG. 13C is the end view of the valve body of FIGS. 13 and 13A.

FIG. 13D is a side detail view of the valve body of FIGS. 13C and 13D.

FIG. 14 is a side sectional view of another modified embodiment.

FIG. 15 is a side sectional view of another barrel assembly.

FIG. 15A is a bottom view of the barrel assembly of FIG. 15.

FIG. 15B is a sectional view taken on line 15B--15B on FIG. 15A.

FIG. 15C is a detail view of a cartridge for use in the barrel assemblyof FIGS. 15 and 15A.

FIG. 16 is a side sectional view of another modified barrel assembly.

FIG. 17 illustrates a modified syringe embodiment, having parts shown insection.

FIG. 18 is a side elevation view of another barrel assembly having partsshown in section.

FIG. 19 is a side view of a modified power syringe handle.

DETAILED DESCRIPTION

Referring to the drawings, there is best seen in FIG. 1 an all purposedental syringe 20 which, as will be herein described, can be utilized todispense virtually all of the currently, commonly used, dental materialsas may be required in the performance of various dental procedures. Forexample, the syringe 20 may be used to inject an anesthesia; it can beused to dispense and position dental impression material which may be aviscous rubber like material; it can be used to dispense a root canalmaterial in a minute root canal; it can be used to dispense a compositeresin material to restore a tooth, it can be used to store or dispenselight settable dental material, it can be used to dispense ahydrocollid, and other flowable materials. The dental syringe 20comprises essentially of a power handle 21 to which a plurality ofreadily interchangeable barrel assemblies can be attached, e.g. thevarious barrel assemblies shown in FIGS. 5 to 18, as will be hereinafterdescribed. Each barrel assembly is constructed to effect the dispensingof a given material, and each barrel assembly is constructed todetachably connect to the power handle 21.

In the illustrated embodiment the power handle 21 is defined by a pairof complementary handle sections 22 and 23, which are generally similarin outline, but opposite in hand. The respective handle sections 22 and23 can be formed generally of a suitable casting or stamping, or moldedin the shape of a pistol grip. Each handle section 22 and 23 is providedwith a circumscribing flange 22A, 23A which when assembled mate with oneanother. As best seen in FIG. 2, each section is provided with a pair ofcomplementary bosses 24, 25 which when assembled are disposed inalignment. One boss, e.g. boss 25 is provided with a tapped hole 25A andthe other boss 24 formed with a drilled hole 24A. A screw fastener 26extended through the aligned bosses 24, 25 secures the respective handlesections in assembled position. Referring to FIGS. 1 and 4, the handlesection 23 has connected to the upper end thereof a barrel mount 26. Thebarrel mount 26 is defined as an annular ring or collar which isintegrally connected to one of the handle sections and which isinternally threaded at 27. The respective handle sections 22, 23 areformed so that in the assembled position the front end of the assembledpower handle 20 is provided with an opening 28 for accommodating atrigger 29. The trigger comprises an elongated member having a pivothole 30 extending therethrough. The trigger 29 in the assembled positionof the handle 20 is pivotably disposed between the handle sections 22,23 by extending the upper bosses 24, 25 through the pivoting hole 30. Apig tail spring 31, coiled about the upper aligned bosses 24, 25; andhaving its respective ends 31A and 31B biased against the trigger 29 andthe rear wall of the assembled handle sections, maintains the triggerunder a spring bias. As best seen in FIG. 2, the trigger 29 is definedas a generally U-shaped member in cross section having spaced apart sideflange portions 29A, 29B and an interconnecting front web portion 29C.The trigger adjacent its upper end is provided with a shoulder 32 whichis disposed opposite to a holding pawl means 33. The holding pawl means33, as will be hereinafter described, functions to prohibit any backlashof the plunger 34, and it also functions to prohibit any unintentionalseparation of the plunger 34 from the handle 20 when the plunger isretracted.

The respective flanges 22A and 23A of the respective handle sections arefurther provided with aligned bearing portions 35 and 36 foraccommodating the plunger shaft 34A of plunger 34. The arrangement issuch that the plunger shaft is reciprocally mounted within the alignedbearing portions 35 and 36. The leading end of the plunger shaft 34terminates with a threaded nipple or tip 37. Immediately adjacent thethreaded tip 37 is an annular limit or stop groove 38. The other end ofthe plunger shaft is provided with a pull knob 39. Longitudinally spacedalong a lower circumferential portion of the plunger shaft 34A are aseries of ratchet teeth 40. The arrangement is such that the plungershaft is freely rotatable within its bearing mounts 35 and 36 so thatthe ratchet teeth 40 can be rotated into and out of engagement with adrive means as will be hereinafter described. If desired, the pull knobmay be provided with an indicator or projection 39A to indicate therelative position of the ratchet teeth to its drive means.

The drive means for effecting the incremental advance of the plunger 34comprises a ratcheting pawl 41. The ratcheting pawl is pivotably mountedbetween the flange portions 29A and 29B of the trigger 29 about a pivotpin 42. A pawl spring 43 is coiled about the pivot pin 42 with its endsdisposed so as to normally bias the ratchet end 41A of the pawl intoengagement with the teeth 40 of the plunger. In the illustratedembodiment the ratchet pawl 41 includes a side flange 41B which followsan incline cam 43A formed on the internal surface of handle section 23,as best seen in FIG. 4. The riding of the ratchet side flange 41B on theinclined cam 43A functions as a means for effecting positivedisengagement of the ratchet pawl 41 from the plunger ratchet teeth 40upon the release of the trigger and when the trigger is in its normalinoperative position as seen in FIG. 1.

As will be evident in FIG. 1 each time the trigger is squeezed, i.e.move to the right as seen in FIG. 1, the upper end of the trigger isrotated counterclockwise about the pivot 25 causing the ratchet pawl toride up cam 43A and engage the ratchet teeth 40 of the plunger 34 toadvance the plunger to the left. In FIG. 1, the plunger 34 isillustrated in a maximum advanced position.

To prevent any backlash or tendency of the plunger 34 to retract uponthe release of the trigger 29, a holding pawl means 33 is provided. Theholding pawl means 33 includes a pawl 33A which is pivotably mountedbetween the handle sections about a pivot pin 45. A pawl spring 46 iscoiled about the pivot pin 45 so that the ends of the spring 46 effect abias on the pawl 33A to normally maintain it biased against the ratchetteeth 40. Thus when the trigger 29 is released to return the ratchetpawl 41 to its inoperative position as shown in FIG. 1, the holding pawl33A will prohibit any retraction or backlash of the plunger 34.

The power handle is also provided with a means for adjusting the throwof the trigger and thereby control the linear advance of the plunger 34each time the trigger is squeezed. As it will become evidenthereinafter, the amount of plunger advance will control the amount ofdental material to be dispensed. The adjusting means comprises anelongated slot 50 formed in the handle section 22. A stop pin or buttom51 is slidably disposed in slot 50. In the illustrated embodiment thestop pin or button has three adjusting positions; A, B and C.Co-operatively associated on the trigger 29 and adjacent the slot 50 area series of detents or stops 52A, 52B, 52C. The detents or stops 52A,52B and 52C correspond with pin positions A, B and C respectively. Itwill be apparent that in the assembled position the shifting of the pin51 to positions A, B or C will engage the corresponding detent or stop51A, 51B or 51C to limit the angular displacement of the trigger andthereby control the movement of the ratchet pawl 41 and thecorresponding plunger advance accordingly. In the embodiment shown,maximum plunger advance is achieved when the slide pin 51 is disposed inPosition A and that minimum plunger advance is had when the slide pin 51is disposed in position C. Position B provides for an intermediateadvance of the plunger 34.

In accordance with this invention a plurality of barrel assemblies areinterchangeably connected to the barrel mount 26 of the power handledescribed. As will be described each of the barrel assemblies as shownin FIGS. 5 to 18 are constructed to hold and dispense a particular typeof dental material depending upon a given dental procedure to beperformed. The barrel assembly 60 as shown in FIG. 1 and in FIG. 5 isconstructed to dispense a rubber base type or like impression material.Thus the barrel assembly 60 comprises an elongated tubular barrel 61having a threaded end portion 61A which can be readily threaded to thebarrel mount 26. The other end of the barrel 61 is also externallythreaded at 61B. As best seen in FIG. 5, the end 61B of the barrel isprovided with an inturned flange 62 to defend an end opening 63. An endcollar 64 having a central opening 64A is threaded to the end 61B of thebarrel. Extended through the opening 64A of the collar 64 is adispensing nozzle or tip 65. The dispensing nozzle or tip is preferablyformed of a readily expendible plastic material, and is similar to thosetips disclosed in my prior U.S. Pat. Nos. 3,581,359 and D-224,655, butwithout the plug.

Connected to the end of the plunger shaft is a plunger tip 66 forcomplementing the barrel assembly 60. As shown the plunger tip 66 isprovided with a diameter which snugly engages the internal walls of thebarrel 61. A sealing O ring 67 may be provided so as to effect apositive seal with the internal walls of the barrel 60. The plunger tip66 is threaded to the threaded tip 37 of the plunger shaft 34A as seenin FIG. 1.

In this embodiment it will be noted that the threaded end 61A is of adifferent size than the other threaded end 61B. Thus the arrangement issuch that barrel 61 can only be threaded to the barrel amount with end61A.

In operation, the entire length of the barrel 61 may be filled with animpression material, and with the plunger 34 disposed in its retractedposition, the loaded barrel 61 can be readily fitted to the powerhandle. The disposable nozzle tip 65 is then fitted to the other end 61Bof the barrel 61 by collar 64. With plunger tip 66 connected to theplunger shaft 34A the syringe 20 is ready to dispense a rubber baseimpression material by squeezing the trigger. With the ratchet teeth 40of the plunger disposed in engagement with the ratchet pawl 41, theplunger is advanced to extrude the impression material through thenozzle 65 as the trigger 29 is squeezed. By adjusting the position ofthe pin stop 51, more or less of the impression material may be extrudeddepending upon the setting of the pin stop 51 upon each actuation of thetrigger.

FIG. 6 is directed to a modified barrel assembly 70 which can beinterchangeably connected to the barrel mount 26 of the power handleconstruction described with respect to FIGS. 1 through 4. The barrelassembly 70 when connected to the power handle 21 defines a dentalsyringe for injecting intralignmentary anesthesia. As shown theanesthesia barrel assembly 70 comprises an elongated tubular barrel 71which may be formed of a transparent plastic material to providevisibility. One end of the barrel 71 is provided with a series ofexternal threads as indicated at 71A whereby the barrel 71 can bereadily connected to the barrel mount 26 of the power handle 21. Theother end of the barrel 71 is externally threaded at 71B. Connected toend 71B of the barrel 71 is an end tip 72 which is provided withinternal threads for mating to the threaded end 71B. Projecting from thefront end of the tip 72 is a nipple 73 to which a conventional typeanesthesia needle 74 can be readily connected and disconnected. Thebarrel 71 is sufficiently long so as to receive an anesthesia carpule 75of standard construction. The standard anesthesia carpule 75 comprisesan elongated glass envelope 75 containing the anesthesia and which isgenerally sealed at one end with a diaphragm 76, which is adapted to beperforated by the rear portion of the anesthesia needle 74 so as toplace the needle 74 in communication with the anesthesia stored withinthe glass envelope 74A. The other end of the glass envelope is closed bya piston 76A, which is displaceable disposed within the envelope 75A ofthe carpule 75. To effect displacement of the piston 76A, the threadedtip end 37 of the plunger 34 has connected thereto a plunger tip 77which is specifically shaped to engage the piston 76A so as to effectthe displacement of piston 76A as the trigger 29 of the power handle isactuated, to advance the plunger 34. The anesthesia syringe as describedwith resect to FIG. 6 is such that the barrel 71 in addition tosupporting the anesthesia carpule 75, also functions to confine theglass of envelope 75A of the carpule in the event that the glassenvelope should break during the administration of the anesthesia. Inthe event of such accident, the patient is positively protected frombroken glass. By setting the adjustment button 51 to positions A, B orC, the amount of anesthesia which is to be injected can be controlledaccordingly by the dentist.

The anesthesia syringe as described with respect to FIG. 6 can also bereadily utilized by the dentist to dispense a hydrocolloid. To adapt theanesthesia syringe barrel of FIG. 6 for dispensing a hydrocolloid, ahydrocolloid carpule and its associated needle is substituted for theanesthesia carpule 75 and its needle. Thus, the anesthesia syringebarrel assembly 71 as described can be effectively utilized to injecteither an anesthesia or a hydrocolloid material for taking impressions.

FIG. 7 illustrates another modified barrel assembly 80 which is readilyinterchangeable with the other barrels herein described so as to definethe syringe tool applicable for injecting a root canal material in theprepared root canal of a tooth during the root canal procedure. As shownin FIG. 7, the root canal barrel assembly so comprises an elongatedtubular barrel 81 formed with external threads at one end 81A forthreading to the barrel mount 26 of the power handle 21. The other end81B of the barrel 81 is provided with internal threads to which a tip 82is detachably connected. It will be understood that the tip 82 isprovided with external threads 83.

In the illustrated form of the invention the tip 82 is provided at itsrear end with a chamber portion 84 to define a reservoir for containinga supply of root canal material 85. The reservoir or chamber 84 isconnected in communication to a passageway 86 which projects forwardthereof and through the extended nipple portion 87 of tip 82. Connectedto the end of the nipple 87 is a needle 88 which defines the dispensingnozzle for directing the root canal material disposed in in chamber 84into the minute root canals of a tooth.

To extrude the root canal material 85 the plunger 34 has connected tothe tip 37 end a plunger tip 89 which complements the reservoir chamber84 as shown in FIG. 7. The plunger tip 89 is provided with a tapped hole89A whereby it can be reaidly threaded to the trheaded tip 37 of theplunger 34. The other end of the plunger tip is provided with an annulargroove 89B for accommodating a sealing O ring 89C. It will be apparentthat the O ring 89C is sized so as to be snugly received within thechamber 84 so that the material in advance of the plunger tip 89 isextruded through the needle 88, as the plunger is advanced into thereservoir 84.

In operation, the chamber or reservoir 84 in the tip end 82 of thebarrel assembly is filled with the appropriate root canal material bythe dentist and the tip attached to the barrel 81, as shown. Ashereinbefore described the amount of material which can be extrudedthrough the needle or nozzle 88 can be readily controlled by the dentistby setting the adjustment stop to position A, B or C. To provideadditional visibility of the chamber 84, the barrel 81 is provided witha series of circumferentially placed slotted openings 81C. It will thusbe apparent that barrel assembly 80 can be readily interchanged withbarrel assemblies 60 and 70 for adapting syringe 20 for yet anotherdental procedure.

FIG. 8 illustrates another barrel assembly 90 which can be readilyinterchanged with the other barrels hereinbefore described to define asyringe for delivering a composite resin or other dental type cementsduring a restorative procedure. In FIG. 8, the barrel assembly 90comprises an elongated tubular barrel 91 having one end 91A threadedexternally so as to accommodate the threads of the barrel mount 26 thepower handle 21. The other end of the barrel 91B is provided with aninturned flange 92 to define a front opening 23. The sides of the barrel91 adjacent to the front end 91B are provided with a plurality ofcirumferentially spaced breach openings 94, as best seen in FIG. 7A.Three such breach openings 94 are circumferentially spaced about the tipend of the barrel 91. Extended through the opening 93 of barrel 91 is adispensing nozzle 95. The dispensing nozzle has a reservoir section 96which communicates with a dispensing nozzle tip opening 96A. The nozzletip 95 may be of the type as described in my U.S. Pat. Nos. 3,581,399;3,900,545 or Des 224,655. According to this invention, the compositeresin or dental cement 97 is disposed within the nozzle tip. The rearopen end of the nozzle 95 is sealed with a plug 98. The arrangement issuch that the nozzle 95 can be readily inserted through opening 93 bypassing it through any one of the side breach openings 94.

To effect displacement of the plug 98 to express the composite resin orcement from the nozzle 95, the tip end 37 of the plunger shaft 34 isprovided with a plunger tip 99 which complements the nozzle 95. It willthus be apparent that as the plunger 34 is advanced toward the nozzle95, that the plunger tip 99 will engage the plug 98 to force thecomposite resin or cement 97 ahead of it out through the dispensingorifice 96A.

FIG. 9 illustrates another modified barrel assembly 100 which can bereadily adapted to the barrel mount 26 of the power handle 21 ashereinbefore described. In this form of the invention, the barrelassembly 100 includes an integrally molded or formed member whichincludes a barrel portion 101 and an integrally connected elongatednozzle portion 102. The end 101A of the barrel portion 101 is providedwith a full open end that is externally threaded so as to accommodatethe internal threads of the barrel mount 26. In the form of theinvention disclosed in FIG. 9, the discharge end 102A of the elongatednozzle portion 102 can be initially sealed, as shown, or formed with adischarge orifice. In accordance with this form of the invention, thebarrel portion 101 of barrel assembly 100 defines reservoir or chamberfor containing the dental material 104. By making the barrel assembly100 of a light impervious material or light opaque material, the barrelassembly 100 can be utilized for storing and dispensing a light settabletype dental material. The rear or open end 101A is closed by an end plug103, which may also be formed of a light opaque material to confine orseal the dental material 104 within the barrel portion 101. The end plug103 can be provided with a tapped hole 105 in the rear end thereof toaccommodate the threaded tip 37 of plunger 34 of the power handle whenthe barrel 100 is connected thereto. The end plug 103, as shown, isprovided with a pair of spaced apart circumscribing wippers of flanges103A which are disposed in sealing engagement with the internal walls ofthe barrel portion 101. While the dental material 104 confined withinthe barrel portion of barrel assembly 100 may comprise any type ofdental material, by making the barrel assembly 100 of a light opaquematerial, the barrel assembly can be utilized for storing and dispensinga light settable material. With the construction disclosed in FIG. 9,the barrel assembly 100 can also be utilized as the carrier or containerin which such dental materials, as hereinbefore described can bemarketed, and the container thus becomes an operative component part ofthe syringe by which the material is dispensed. In such case the dentistcan readily attach the barrel assembly 100 to the power syringe handle20 hereinbefore described and by snipping the end 102A an appropriateorifice is formed through which the dispensing material 104 can bedispensed. A sealing cap 115, as shown in FIG. 11, provides the closureto reseal the discharge orifice defined by snipping end 102A.

FIG. 10 is another modified embodiment of a barrel assembly of the typeillustrated in FIG. 9. As shown in FIG. 10, the barrel assembly 110contains a barrel portion 111 similar to that described with respect toFIG. 9. Connected to the barrel portion 111 is an elongated nozzle 111A.The other end 111B of the barrel portion 111 is provided with a fullopen end which is externally threaded so as to complement the internalthreads of the barrel mount 26 of the power handle syringe 20 ashereinabefore described. Adjacent to the tip end of the nozzle portion111A there is provided a series of surrations or threads 112 to whichthere is detachably connected and frictionally secured a nozzle tip 113.An end plug 114 similar to end plug 103A of FIG. 9 seals the open end ofthe barrel portion 111 to confine the material within the barrel portion111. The rear end of plug 114 is also provided with a tapped opening forreceiving the threaded end 37 of plunger 34 when the barrel assembly 110is connected to the barrel mount of the power handle hereinbeforedescribed. It will be understood that the barrel assembly 112 can beutilized to contain the same dental materials as described with respectto the embodiment of FIG. 9. By forming the barrel assembly 110 of alight opaque material, the barrel assembly can be readily adapted fordispensing light settable materials. The dispensing nozzle 113, which isdetachably connected to the nozzle end 112 of the barrel assembly 110,may be of the type described in my U.S. Patents hereinbefore noted. Suchnozzles 113 are readily disposable and can be readily disposed aftereach use. Thus the barrel assembly 110 provides an arrangement wherebythe barrel when connected to the power handle defines a syringe whichcan be used in performing procedures or different patients simply byattaching a new disposable nozzle 113 for each patient.

After use and during storage, the open end or orifice of the nozzleportion 102 and 111A of FIGS. 9 and 10 can be resealed by an end cap115, disclosed in FIG. 11.

The barrel assemblies of FIGS. 9 and 10 may be formed of a plasticmaterial and thus provide for a relatively inexpensive and disposablecontainer for the and thus material disposed therein and which alsofunctions as a syringe component.

FIG. 12 illustrates still a further modified barrel assembly 120. Barrelassembly 120, when formed of a light opaque or light impervious materialand preferably of plastic, can be readily used as a container anddispenser for light settable materials. As shown, the barrel assembly120 comprises a barrel portion 121 which is externally threaded at 122with threads for complementing the threads of the barrel mount 26 of apower handle. Thus the barrel assembly 121 can be rendered detachablyconnected to the power handle as hereinbefore described. Adjacent thefront end of the barrel portion 121 there is provided an externalthreaded portion 123. Projecting beyond the front end of the barrelportion 121 is an elongated nozzle portion 124. A threaded collar 125having a front opening 126 is connected at 123 to the barrel portion121. As shown, a disposable nozzle tip 127 extends through opening 126of collar 125 so as to receive and accommodate the nozzle portion 124 ofthe barrel assembly 120. In the arrangement described with respect toFIG. 12, the disposable nozzle 127 together with nozzle portion 124forms a double wall dispensing nozzle tip. The nozzle tip 127 alsofunctions as a rotatably directional control tip for precisely directingthe extrusion of the material from the barrel assembly 120. It will beapparent that the nozzle tip 127 can be rotated a full 360° within itsopening 126 to precisely control the direction and deposit of thematerial extruded. Also, the nozzle 127 forms a protective nozzle forthe nozzle portion 124. Materials contained within the barrel 121, whichmay be a light settable material, is a very viscous material. The bore124A extending through the nozzle portion 124 relative to the diameterof the barrel forms a relative minute passageway. Therefore, when thematerial is extruded, the nozzle portion 124 is subjected to relativelylarge pressures which may cause the nozzle portion to rupture. Theexterior nozzle tip 127 thus functions as a means for confining thematerial in the event the nozzle portion 124 should rupture during adispensing operation. In the barrel assembly described, the nozzle tip127 is positively attached to the front end of the barrel by collar 125.In addition to the threaded connection being herein described, it willbe understood that other positive types of connections may be used suchas a bayonet type connection or other secured mechanical connections maybe utilized. With the construction described the readily removable anddisposable exterior nozzle tip 127 also functions to prevent crosscontamination between patients, and the curved outer nozzle 127 allowsthe dentist to accurately dispense the appropriate amount of material insmall and/or difficult to reach areas.

It will be understood that after the syringe with barrel assembly 120has been used, the nozzle 127 can be readily disposed and the open tipend of the nozzle portion 124 can be resealed with a sealing cap 115 ofthe type disclosed by FIG. 11. Thus the barrel assembly 120 comprises arelatively large tube for containing a relatively large supply of dentalmaterial which can be readily secured to the power portion or mountingportion 26 of the power handle to form a syringe as described withrespect to FIGS. 1 thru 4; and provides a means for storing the materialbetween uses.

The rear open end of the barrel portion 121 is closed by a plug 129similar to that hereinbefore described. If desires, the end plug 129 maybe provided with a tapped hole in the end thereof for receiving thethreaded tip 37 of a plunger 34. As an alternative it will be understoodthat the tip 37 may be provided with a plunger tip (not shown) arrangedto abut against the rear end of plug 127 to effect the displacementthereof during an extrusion operation instead of being connectedthereto.

FIG. 13 illustrates another modified barrel assembly 130 which may beinterchangeably used in conjunction with the power handle to form thesyringe. As shown in FIG. 13, the barrel assembly 130 comprises a barrelportion 131 which is fully open at one end 131A and has an elongatednozzle portion 133 integrally connected to the other end of the barrelportion 131. The end 131A of the barrel portion 131 is provided with anexternal thread 132 whereby the barrel assembly 130 can be readilyattached to the mounting portion 26 of a power handle as hereinbeforedescribed.

The elongated nozzle 133 is provided with a series of external threads134 located adjacent the front end of the barrel. Detachably connectedto the nozzle portion 133 is a dispensing nozzle or tip 135 which may beformed of a readily disposable material and which nozzle or tip 135 issimilar to that disclosed in my U.S. patents hereinbefore cited. Asshown the nozzle or tip 135 is provided with an angularly disposeddischarged orifice 136. On the other or rear end of the nozzle or tip135 there is provided an internal thread 137 adapted to complement thethreads 134 on the nozzle portion 133. By mating the complementarythreads 137 and 134, a positive means is provided for securing thenozzle 135 to the nozzle portion 133. It will also be understood thatthe nozzle 135 can be rotated through 360° so as to control thedirection in which a dentist desires to direct the discharge orifice136.

As disclosed in my U.S. patents herein cited, the disposable nozzle 135is formed of a readily expendible thermo-plastic material. Such materialcan also be rendered self threading and therefore need not be providedwith formed threads 137 as disclosed in FIG. 13. By maintaining theproper tolerances between the internal diameter of the nozzle 135 andthe external threads 134, the nozzle 135 can be self threaded onto thenozzle portion 133. The open end of the barrel portion 131 is sealed bya plug 139 similar to that described with respect to FIG. 12, or may beprovided with a projecting tip end 139A to displace material in thenozzle portion 133. In this form of the invention the disposable nozzle135 functions in a manner similar to the nozzle 127, described withrespect to FIG. 12. Nozzle 135 functions as a means for controlling thedirection of dispensing the material stored within the barrel portion131, as well as forming a double wall nozzle dispensing means to preventany loss of material in the event that the inner nozzle portion 133should rupture during an extruding procedure. Also, the disposablenozzle 135 provides a means for preventing cross contamination betweenpatients.

FIG. 14 illustrates still another modified barrel assembly. The barrelassembly 140 comprises a barrel portion 141 which is threaded at itsrear end 142 whereby the barrel assembly 140 can be readily threadedinto the barrel mount 26 of the power handle. The other end of thebarrel is provided with an extended nozzle portion 143 similar to thathereinbefore described. The material to be dispensed is contained withinthe barrel portion 141 in a manner hereinbefore described. For storing alight settable material in the barrel assembly 140, it will beunderstood that the barrel assembly 140 is made of a light impervious orlight opaque material.

In embodiment of FIG. 14, the front end 144 of the barrel portion 141 isprovided with a circumscribing recessed portion 145 which is adapted toaccommodate a laterally extending flange 146 which circumscribes therear open end of a disposable nozzle 147 of the type described in mycited U.S. patents. As best seen in FIG. 14, the lateral flange portion146 of a disposable nozzle 147 is snap fitted into the annular recess145 so as to retain the nozzle 147 in position during an extrudingoperation. Because the material contained within the barrel portion 141is generally a viscous material wich is extruded through a very narrowor small diameter passageway of the nozzle portion 143, extreme pressureis required. Therefore, a positive means must be provided for retainingthe disposable nozzle 147 securely fastened to the front end of thebarrel portion 141. The disposable nozzle 147 thus functions in a mannersimilar to that described with respect to FIGS. 12 and 13.

The rear end of the barrel portion 141 is sealed by an end plug 149similar to that hereinbefore described.

It will be understood that the material contained within the barrelportions of the modifications disclosed in FIGS. 12, 13 and 14 maycomprise composite resins, dental cement, light settable materials,impression material and other various materials used by dentists as maybe required for the various dental procedures. It will also beunderstood that the barrel assemblies 120, 130 and 140 may be made of adisposable plastic material whereby the entire barrel assembly may bediscarded upon the exhaustion of all the dental material carriedtherein. Also, while the power syringe and the various barrel assembliesherein disclosed and described are particularly adapted for use by adentist, the power syringe; as described, may have application for usein other fields of endeavor. For example, the power syringe describedcan be utilized as an aid in orthopedic surgery for the placement ofbone cement to aid in the cementing of certain orthopedic replacementparts such as hip joints. For surgical use the barrel assembly may beprepackaged in a sterile manner ready for use. The bone cement is mixedwhen the prosthesis is ready for cementing, and is placed into the largeend of the barrel portion by the surgeon. The end plug is then placed inthe end of the barrel portion and the tube assembly onto the powerhandle. The surgical material within the tube is then expressed in amanner as hereinbefore described.

FIGS. 15, 15A, 15B and 15C illustrate another modified barrel assemblywhich can be interchangeably utilized with the power handle ashereinbefore described. The barrel assembly 150 of FIGS. 15, 15A and 15Bis constructed so as to be utilized with a relatively large cartridge157 adapted to be filled or prefilled with a dental material ashereinbefore described. In this form of the invention the barrelassembly 150 includes a tubular barrel 151 which is threaded at one end152 whereby it can be readily secured to the barrel mount 26 of thepower handle. The front end 153 of the tubular barrel 151 is providedwith a front wall 154 having a slotted or arcuate shaped front opening155 therein. Preferably the arcuate opening 155 is sized so as toreceive and retain the nozzle portion 156 of a cartridge 157 as will behereinafter described. The tubular barrel 151 is also provided with aside or breach opening 158 which is disposed in communication with thefront opening 155 as best seen in FIG. 15A. It will be understood thatthe barrel portion 151 can be readily threaded or secured to the barrelmount 26 of the handle.

The barrel assembly 150, as described, is specifically arranged so as toreceive a cartridge 157 which contains the dental material to beextruded. As shown the cartridge 157 comprises an elongated tubular bodyportion 157A which has a length greater than that of the breach opening158 as best seen in FIG. 15A. The body portion 157A defines a reservoirwhich is open at its rear end 157B and which has connected to its otherend an integrally connected elongated nozzle portion 156. As best seenin FIG. 15A, the cartridge 157 is inserted into the barrel 151 by firstinserting the end 157B of the cartridge into the side opening 158 andthen snap fitting the nozzle 156 in position through the arcuate frontopening 155 as best seen in FIG. 15A. It will be understood that the endof the reservoir or body is sealed by an end plug 159 similar to thatdescribed with respect to FIG. 12, 13 and 14. With the materialcartridge 157 disposed within the barrel portion 151 and the barrelportion secured to the barrel mount 26 of the power handle, the materialin the cartridge 157 is readily expressed by squeezing the trigger ofthe power handle in a manner herein described. If desired, a disposablenozzle tip may be connected to the nozzle portion 156 similar to thatdescribed with respect to FIGS. 12 and 14. By disposing the disposablenozzle, which is similar to nozzles 127, 135 and 147, to the extendednozzle portion 156 will render the assembly of FIG. 15 operative in amanner described with respect to FIGS. 12 thru 14.

FIG. 16 illustrates another modified barrel assembly 160 for receiving acartridge 161 containing a supply of dental material. As hereinbeforedescribed the dental material contained within the body portion 161A ofthe cartridge 161 may comprise a composite resin, dental cement, lightsettable material, impression material or any like material used by adentist during a dental procedure. For a cartridge containing a lightsettable material, it will be understood that such cartridge 161 beformed of a light impervious or light opaque material. The cartridge161, as hereinbefore described, can be readily formed of a disposableplastic material so that when its content has been exhausted; thecartridge 161 may be disposed.

In this form of the invention, the barrel assembly 160 comprises anelongated tubular member to define a barrel which can be interchangeablyconnected to the barrel mount 26 of power handle of the typehereinbefore described. One end of the barrel is provided with a seriesof external threads 162 whereby it can be detachably connected to abarrel mount 26. The other end of the barrel is also provided withexternal threads 162. A flanged collar 164 having a front opening 165 isthreadedly connected to threads 163. As shown, the cartridge 161 can beloaded through either end of the barrel 160. Integrally formed to thefront end of the cartridge 161A is an elongated nozzle portion 161B. Toprovide directional control to the material being extruded during anextruding operation, a disposable nozzle or tip 166, similar to thathereinbefore described, is utilized to circumscribe the nozzle portion161B of the cartridge 161. As shown the nozzle 166 is fitted over thenozzle portion 161B, and is retained to the end of the barrel by thecollar 164. The arrangement is such that the nozzle 166 can be rotated afull 360° so as to give the dentist control over the direction in whichthe material is to be extruded. The rear end of the cartridge 161 isclosed by an end plug 167. The end plug may be constructed similar tothat described with respect to the end plugs of FIGS. 12 13, 14 and 15;or as an alternative construction, may be provided with an elongatedprojecting portion 167A arranged to extend into the nozzle portion 161Bduring the final stages of extrusion. By providing an elongatedprojection 167A on the end plug 167 the material which is otherwiseconfined to the nozzle portion 161B can be extruded therefrom andthereby minimizing the amount of waste otherwise necessitated. Ashereinbefore described, the disposable nozzle 166 provides directionalcontrol in addition to functioning as a double walled nozzle, whenutilized in conjunction with the nozzle portion 161B. Also thedisposable nozzle 166 prevents cross contamination between patients.

The barrel assembly as described with respect to FIGS. 5 thru 18 and theassociated cartridge 157, when used, as herein described can be readilyadapted for use in a modified syringe handle construction as shown inFIG. 17. The handle construction shown in FIG. 17 comprises a firstfixed handle portion 170 which has a threaded bore 171 disposedintermediate the ends of the handle portion 70. Pivotably mounted to thefixed handle portion 170 is a movable handle member 172. The barrelassembly and/or the barrel assembly including a cartridge containing thedental supply material as hereinbefore described can be readilydetachably connected to the threaded bore 171. A plunger 174 extendedinto the rear end of the barrel to engage either the plug sealing thedental material within the barrel; or in the event of a cartridge, thplug sealing the rear end of the cartridge containing the dentalmaterial to effect the displacement thereof to extrude the materialtherefrom.

From the foregoing it will be apparent that this invention is directedto an improved syringe barrel and/or cartridge construction for storingand dispensing a dental material as for example composite resins, dentalcements, light settable material, impression material, anesthesia,hydrocolloids and the like; and which supply of material can beincrementally dispensed in relatively small varying amounts as may berequired. Also, such cartridges and/or barrel assemblies can beinterchangeably used with a single, common syringe handle to define asyringe by which relatively viscous dental materials can be accuratelyand precisely dispensed through a very fine discharge apperture ororifice to effect a controlled deposit of the material where needed. Inthe various embodiments herein illustrated an improved delivery systemis provided whereby efficiency and use of relatively expensive dentalmaterial can be maximized with a minimum of waste. The illustratedsyringe further provides the dentist with a delivery system which can beused in a variety of dental procedures, thus greatly reducing the numberand kinds of tools and implements otherwise required to perform thevariety of dental procedures.

FIG. 18 illustrates a modified barrel assembly which may be utilized foraccommodating a cartridge construction described with respect to FIG.15C. The barrel assembly 170 of FIG. 18 comprises an elongated tubularmember 171 having an open rear end portion 172 circumscribing threads orother securing means 173 whereby it can be readily detachably connectedto the barrel mount of a syringe handle 21 of FIG. 1 or handle 170 ofFIG. 17. The front end of the barrel portion 171 is provided with acircumscribing end wall 175 to define a front aperture 176. Disposedintermediate to the length of the barrel 171 is an enlarged side breachopening 177. The breach opening 177 is sufficiently large so as toreceive the capsule 157 as described with respect to FIG. 15C. Insertionof the cartridge 157 within the barrel 171 is effected either byinserting the cartridge 157 through the rear open end 172 or byinserting the cartridge through the side breach 177. When insertedthrough the side breach 177, the rear end of the cartridge 157 must befirst inserted through the side opening 177 and pushed sufficientlytowards the rear of the barrel so as to permit the insertion of theelongated nozzle portion 156 through the front aperture 176. If desireda disposable nozzle 166 may be inserted through the front end of thebarrel 171 in advance of the cartridge 157. Thus the nozzle 166 andnozzle portion 156 provides a directional double wall nozzle arrangementto confine the material being extruded so as to permit a dentist to havedirectional control in depositing the material during a dentalprocedure. The external nozzle tip 166 further functions to confinematerial therein in the event of any rupture of the nozzle portion 156during an extruding operation.

In accordance with this invention, the various barrel components, e.g.the barrel components of barrel assemblies 60, 70, 80 and 90 and theirrespective associated plunger tips 66, 77, 89 and 99 may be color codedso that a dentist can readily and quickly set up the syringe for aparticular procedure. For example, the barrel 60, its end collar 62 andplunger tip 66 for expressing the impression material may be likecolored, e.g. gold. The corresponding barrel and plunger tips forexpressing an anesthesia may be colored green. The barrel components forexpressing the root canal material may be colored red, etc. By colorcoding the respective component parts, a dentist can quickly andefficiently assemble the respective syringe components to perform aparticular procedure.

It will be understood that the disposable nozzle tips, e.g. nozzle tips65, 95, 113, 166, 127, 135, 147 and 159 are formed with a wall thicknessand dispensing orifice sized necessary to express a given materialdepending upon the viscosity or fluidity of a given material. Forexample, the discharge orifice of a given tip may be sized so as to havea diameter of 1 mm to 21/2mm. The wall thickness of the nozzle tips areproportioned to contain the pressures exerted thereon during anextrusion of the dental material therethrough.

FIGS. 13 to 13D illustrate another important feature of the presentinvention. It will be understood that the feature herein described canbe utilized with any of the particular barrel assemblies hereindescribed where there is a tendency of the material to continue toextrude out the nozzle thereof as a result of any residual pressurebeing imparted to the material. When a material is confined within atube or cartridge and is dispensed therefrom by the application ofpressure on the tube or cartridge, it has been noted that upon releaseof the pressure, a certain amount of the material will continue toextrude out therefrom due to the residual pressure acting on theconfined material. To obviate this inherent loss of material from a tubeor cartridge as a result of such residual pressure acting on thematerial, the present invention contemplates a syringe structure of thetype herein described wherein the tip 37 of the plunger shaft 34A isprovided with a modified plunger tip 200 which functions as aunidirectional valve means to create a vacuum on the end of the sealingplug, e.g. 139 in FIG. 13, to relieve the residual pressure which willotherwise create some unwanted extrusion of material, depending upon thevirosity and pressure of the confined material.

As best seen in FIGS. 13 to 13D, the modified plunger tip 200 comprisesa spool shaped member 201 having an imperforate front face 202 which hasa diameter which is less than the internal diameter of the cartridge orbarrel 131. Disposed between the front face 202 and a rear face 204 thespool 201 there is provided with a reduced body portion 205. The rearpart of the body portion 205 and rear face 204 is provided with a seriesof radial passages or grooves 206, circumferentially spaced therearound.The rear face 204 is further provided with a tapped hole 207 whereby thespool body 205 can be readily threaded to the top end 37 of a plunger34, as hereinbefore described.

Slidably disposed on the reduced body portion 205 is an O ring seal 208.The O ring seal 208 has an outer diameter which will snugly engage theinternal walls of the barrel 131 and create a seal thereat. The functionof the O ring 208 is such as to open the radial passages or grooves 206as the plunger 34 is being projected into the barrel 131 to effect theevacuation of any air that may be trapped between the plug 139 and thefront face 202 of the plunger tip 200 on the extruding stroke of theplunger; and to seal the grooves 206 to create a vacuum on the rear endof the plug 139 to relieve any residual pressure which may tend to acton the material in advance of the plug 131, upon the retraction of theplunger shaft 34A.

In operation, the unidirectional spool valve member 200 is threaded tothe tip 37 of the plunger to define a plunger tip. The front face 202 ofthe plunger tip is placed in driving engagement with the rear end of theplug 139. As the plunger 34 is actuated and is projected with the barrel131 to effect displacement of the plug 139 to extrude the material inadvance thereof, the O ring 208 is forced against the rear face 204 andbehind the front end of grooves 206, thus permitting any air ahead ofthe O ring to be exhausted to the rear of the spool member 205 throughopened grooves 206. When the plunger travel has ceased, the residualpressure developed ahead of the plug 139 and acting on the material Mmay cause a small amount of material to continue to extrude until thepressure on the material has equalized by the expression of this smallamount. As the amount and/or cost of the material may be critical in adental procedure, the extrusion of any excess material upon thetermination of the plunger advance can be controlled with theconstruction described, by retracting the plunger 34.

In retracting the plunger 34, e.g. to the right as viewed in FIG. 13A,the sealing friction of the O ring 208 on the walls of the barrel willcause the ring 208 to be disposed or shifted adjacent to the front end202 of the spool 200, thus closing off grooves 206. As air is prohibitedfrom passing seal 208 upon retraction of the plunger tip 200, a vacuumis created in the space between the plug 139 and the front face 202 ofthe plunger tip 200 which will effect a slight retraction of the plug139 to thereby relieve the residual pressure which would otherwiseresult to expressing unwanted material from the barrel. It will beapparent that with this construction a simple and expedient solution isachieved to a sometimes disturbing problem.

It will be understood that the unidirectional plunger valve tip 200 asdescribed may be used with any of the barrel assemblies herein describedhaving a displaceable plug, such as plug 139, to force the material outof the barrel or cartridge upon an extruding operation.

FIG. 19 illustrates a modified electrically powered handle means 220which can be readily utilized with the various barrel assemblies ashereinbefore described to define an all-purpose syringe capable ofperforming the various dental procedures herein set forth. In thisembodiment, the power handle means or assembly 220 is defined by a pairof handle sections similar in shape as hereinbefore described. Pivotallyconnected between the handle section is a trigger 221 or button, whichfunctions as a switch means to energize and/or de-energize a high torquereversible electric motor 222 mounted within or on the handle assembly.It will be understood that the power for the motor 222 may comprise asource of battery power 223 dispensed within the handle assembly 220and/or may be connected to a conventional line current. The connectionof the motor 222 in circuit with a battery source 223 renders thesyringe a wholly self contained unit.

Mounted for movement within the handle assembly 220 is a plunger means224 which is arranged to be shifted or moved in either a protractingposition or retracted position. The front of the handle assembly 220 isprovided with a barrel mount 225 to which the various barrel assembliesas herein described can be detachably connected thereto.

A transmission means is operatively interconnected between the motorshaft 222A and the plunger shaft 224A of the plunger means 224; wherebythe rotation of the motor shaft 222A is transmitted to the plunger shaft224A. The transmission means as shown comprises a bevel gear 225 similarto the motor shaft 222A. Bevel gear 325 intermeshes with a ring wormgear 226 rotatably journaled within the handle assembly.

The shaft 224A of the plunger means 224 is provided with an externalworm screw which extends through and meshes with the worm threads of thering worm gear 226. The arrangement is such that upon the actuation ofthe motor 222, the rotation of its shaft 222A is transmitted to theplunger shaft 224A to either advance it into the connected barrelassembly or to retract the plunger shaft depending upon the direction ofrotation of the motor 222. The direction of rotation of the motor can becontrolled by a two position handle means and/or by a proper selectormeans which will arrange the circuit to effect either a forward drive ora reverse or retraction drive for the plunger shaft.

In all other respects, the function and operations of the electric powerhandle 220 and associated barrel assemblies is similar to that hereindescribed with respect to FIG. 1.

In the arrangement described, e.g. in the syringe 20 of FIG. 1, theplunger 34 is manually retracted, first by rotating the plunger shaft todisengage the ratchet teeth from the ratchet pawl 41A; and thenretracting the plunger 34. When the plunger 34 has been fully retracted,the holding pawl with engage the stop groove 38, and thereby prohibitany unintentional removal or separation of the plunger shaft from thehandle 21. However, if the dentist wishes to intentionally separate orremove the plunger from the handle, e.g. for cleaning or to change theplunger tip or for whatever reason, it can be readily removed by settingthe adjusting button 51 to the highest or A position as seen in FIG. 3,and pushing the trigger upwardly slightly. In doing so, the shoulder 32of the trigger will effect a slight displacement of the holding cam 38sufficient to disengage it from the stop groove 38 which will permitremoval of the plunger 34 from the handle. Thus, the componentsdescribed can be readily separated, but not by accident or withoutintention.

While the syringes herein described have particular application indentistry, they have application in certain medical surgical proceduresas herein described. Also, the syringes described may be used inindustry to precisely control the deposits of industrial materials suchas glues, epoxies and other adhesives and/or fillers.

The present invention further contemplates a syringe construction inwhich the component barrel position may also function as the containeror cartridge in which the dental material may be sold or packaged, andfrom which the material can be readily dispensed as required. Also dueto the viscosity of certain materials, a power handle is providedwhereby a sufficient mechanical advantage is achieved to extrude aviscous material through relatively small and minute passages withconsiderable ease; and whereby the pressure imparted on the material canbe relieved to prohibit any excess extrusion of the material, subsequentto an extruding operation.

While the invention has been described with respect to certainembodiments thereof, it will be understood and appreciated thatvariations and modifications may be made within the scope and spirit ofthe invention.

What is claimed is:
 1. An expendible bulk dispensing cartridge for bothpackaging a dental material and for dispensing a plurality of variableproportions of the dental material contained therein directly to thetooth cavity in different patients without cross contamination,comprising an elongated tubular member formed of a light opaque plasticmaterial and having a reservoir portion, said reservoir portionextending throughout a major portion of said tubular member, saidtubular member having a full open end portion at one end thereof, and anozzle connected to the other end of said tubular member and said nozzlebeing integrally formed with said reservoir portion, said tubular memberhaving means for connecting to a syringe handle, a bulk supply of lightcurable dental material for use on more than one patient disposed insaid reservoir portion, an end plug sealing the full open end of saidtubular member for confining said dental material within said reservoirportion, said end plug being displaceably disposed within said tubularmember whereby the displacement of said plug effects the extrusion ofsaid material through said nozzle, a readily disposable discharge tip,means for detachably connecting said disposable tip to said nozzle, andpermitting said disposable tip to be rotated relative to said nozzle360° for directional control in dispensing said material, saiddisposable tip extending beyond the end of said nozzle whereby saidnozzle is encased wholly within said disposable tip to prohibit anycontact between said nozzle and the tooth being filled, said disposabletip having an angularly disposed discharge opening relative to thelongitudinal axis of said tubular member, and a cap for sealing the endof said nozzle when said cartridge is not in use.